i don't see why it ceased to be kid friendly because of coins. They get some for free, they use them, they understand the value of money in todays society and they go back to playing the free games until they can get a job.
on the other hand Green said this:
I'm not sure people realise that this was added because it is what the community was asking for, and were voting for on uservoice.
which is far from true. no such item was high on uservoice demand and 90% of the players in warlight were taken by surprise. i do agree that it seems to be a welcome addition to the top players, i'm not entirely convinced of it yet, but then again i'm not top player yet either nor have i any particular interest in getting money by playing warlight even though i do enjoy highly competitive strategy gaming. i have a slight fear the highly competitve strategy gaming on warlight will become reduced to coin games only, if that day comes i'll probably retire once i'm out of coins, but so far it hasn't been so, so game on.